Symmetrical Crossovers - Why? - Advantage/Disadvantage

LarsS

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Nov 11, 2014
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I have a pair of Gauder Akustik speakers (ex Isophon), which I'm very happy with. This thread is not about the speakers but the crossovers.

Speakers are equipped with Passive Symmetrical Crossovers with >50dB slope. This type of crossovers is the hallmark of Gauder Akustik.

My questions to you all knowledgeable WBF'ers are as follows (Google has not been my friend in finding this out):

- What are the rationales behind symmetrical crossovers, if any?

- Are there specific demands on the power amplifier driving speakers with symmetrical crossovers with this slope or will they relieve the amp in any way?

- Advantages / Disadvantages (apart from being expensive) with symmetrical crossovers?

/Best
Lars
 

dallasjustice

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Apr 12, 2011
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Most crossovers are symmetrical between drivers. The crossover can make a big difference in the speaker's polar response and distortion. Without measuring, it's impossible to know why a specific crossover was chosen for that speaker. My experience with digital crossovers between subs and full range speakers tell me that symmetrical crossovers are usually the best way to go. But with multiple subs, that may not be the case. I plan on setting up an asymmetrical crossover sub array next week using Acourate. I believe I can get best results this way. We will see.

I have a pair of Gauder Akustik speakers (ex Isophon), which I'm very happy with. This thread is not about the speakers but the crossovers.

Speakers are equipped with Passive Symmetrical Crossovers with >50dB slope. This type of crossovers is the hallmark of Gauder Akustik.

My questions to you all knowledgeable WBF'ers are as follows (Google has not been my friend in finding this out):

- What are the rationales behind symmetrical crossovers, if any?

- Are there specific demands on the power amplifier driving speakers with symmetrical crossovers with this slope or will they relieve the amp in any way?

- Advantages / Disadvantages (apart from being expensive) with symmetrical crossovers?

/Best
Lars
 

Phelonious Ponk

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Jun 30, 2010
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Please explain symmetrical vs asymmetrical crossover. :)

Tim
 

dallasjustice

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I think the proper term would be series vs parallel crossover. I might be wrong.
The OP is asking about symmetrical vs non-symmetrical XO slopes. Sometimes it makes sense to cross one driver over with a steeper slope than the counterpart driver.
 

treitz3

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....only in the lower registers though, correct?

Tom
 

nc42acc

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Nov 10, 2015
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I am sorry I misunderstood. My apologies. Crossover slopes typically are asymmetric to achieve proper phase response. First order designs typically in my experience are more likely to be symmetric.

The OP is asking about symmetrical vs non-symmetrical XO slopes. Sometimes it makes sense to cross one driver over with a steeper slope than the counterpart driver.
 

DaveC

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Nov 16, 2014
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I'm not sure symmetric slope is what he's talking about... Symmetric might mean using the same components on the - leg and the +?
 

nc42acc

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Dave after reading the OP question, what a concept, I think he is asking about infinite slope crossovers. Maybe the OP will clarify?

I'm not sure symmetric slope is what he's talking about... Symmetric might mean using the same components on the - leg and the +?
 

DaveC

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Dave after reading the OP question, what a concept, I think he is asking about infinite slope crossovers. Maybe the OP will clarify?

Yes, I'm not really sure... Magico also claims to use symmetric elliptic crossovers. I'm not sure a passive xo can be infinite slope, but 50 dB can be achieved passively. I think in this symmetric means the layout of the xo parts and not the slope. Slope is determined by driver characteristics for the most part. Gauder uses ceramic drivers so the xo is critical to avoid the nasty regions of the drivers. I have to admit I don't see the attraction to these drivers, in stock form they are not very good sounding... with damping and an overly complicated crossover they can sound ok but I'll take a softer, more well behaved driver anyday.
 

nc42acc

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Nov 10, 2015
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Dave I know Jeff Joseph touts an infinite slope crossover. Myself I am from the old school single order camp. Less is more concept with excellent well behaved drivers.

Yes, I'm not really sure... Magico also claims to use symmetric elliptic crossovers. I'm not sure a passive xo can be infinite slope, but 50 dB can be achieved passively. I think in this symmetric means the layout of the xo parts and not the slope. Slope is determined by driver characteristics for the most part. Gauder uses ceramic drivers so the xo is critical to avoid the nasty regions of the drivers. I have to admit I don't see the attraction to these drivers, in stock form they are not very good sounding... with damping and an overly complicated crossover they can sound ok but I'll take a softer, more well behaved driver anyday.
 

DonH50

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Jun 22, 2010
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I couldn't find anything looking useful through a few pages but probably irrelevant. Crossover design is always a compromise and for any given speaker system the trade among frequency points, slopes, and filter topologies can be tricky.
 

nc42acc

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Crossover design = snake oil, patience, voodoo, good ears and lots of capacitors, inductors and resistors on hand. ;)

Oh and an accurate measurement system.

I couldn't find anything looking useful through a few pages but probably irrelevant. Crossover design is always a compromise and for any given speaker system the trade among frequency points, slopes, and filter topologies can be tricky.
 

DaveC

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Nov 16, 2014
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Crossover design = snake oil, patience, voodoo, good ears and lots of capacitors, inductors and resistors on hand. ;)

Oh and an accurate measurement system.

We do have some modern tools that can model xos digitally:

http://www.woofertester.com/index.htm

Infinite slope should mean just that, a straight vertical line or "brick wall" response. AFAIK, for passive xos the slope will be in multiples of 6 dB/oct, not sure it's really possible to achieve a true brick wall response although a very high order elliptic filter would be close.
 

nc42acc

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Nov 10, 2015
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Dave I have contemplated purchasing LEAP, there are too many online calculators that can get you in the ballpark. As you know the rest is listening and measuring.

I think Joseph has a patent on the infinite slope crossover design.

We do have some modern tools that can model xos digitally:

http://www.woofertester.com/index.htm

Infinite slope should mean just that, a straight vertical line or "brick wall" response. AFAIK, for passive xos the slope will be in multiples of 6 dB/oct, not sure it's really possible to achieve a true brick wall response although a very high order elliptic filter would be close.
 

LarsS

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Nov 11, 2014
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Stockholm
I'm not sure symmetric slope is what he's talking about... Symmetric might mean using the same components on the - leg and the +?

DaveC,

correct, same components on both legs. So many components compared to a "normal" passive crossover.

These are my Gauder Akustik speakers, not equipped with ceramic drivers - - > http://www.gauderakustik.com/pdf/Arcona100-Audio1113.pdf


Back from a glorious day skating in Stockholms archipelago!

Ådfjärden.jpg
 

dallasjustice

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